Device and method for repairing a memory array by storing each bit in multiple memory cells in the array

ABSTRACT

A DRAM array is repairable when the array includes memory cells that are defective because their storage capacitors are unable to retain a sufficient electric charge to properly store “1” and “0” bits. To repair the array, both even and odd row decoders in the array are permanently enabled so that each row address the array receives causes the even row decoder to energize at least one even word line and the odd row decoder to energize at least one odd word line. As a result, at least two memory cells are accessed for each row address so that each “1” or “0” bit is stored as an electric charge in at least two memory cells. By grouping enough memory cells together in this manner to store each “1” and “0” bit, the grouped memory cells are able to retain a sufficient total electric charge as a group to properly store each bit even when individual memory cells in the group are unable to do so.

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is a continuation of application Ser. No.09/618,816, filed Jul. 18, 2000, pending, which is a continuation ofapplication Ser. No. 09/015,541, filed Jan. 29, 1998, now U.S. Pat. No.6,122,213, issued Sep. 19, 2000, which is a divisional of applicationSer. No. 08/775,510, filed Dec. 31, 1996, now U.S. Pat. No. 5,781,483,issued Jul. 14, 1998.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] The present invention relates in general to memory array repairand, in particular, to devices and methods for repairing memory arrays,such as dynamic random access memory arrays, by storing each individualbit in multiple memory cells in the arrays.

[0004] 2. State of the Art

[0005] In general, Dynamic Random Access Memory (DRAM) arrays storedigital information in the form of “1” and “0” bits by storing the bitsas electric charges on capacitors. DRAM arrays then retrieve the storedbits by discharging their representative electric charges to aconductor, such as a digit line, and then detecting a change in voltageon the conductor resulting from the discharge. When any of thecapacitors in a DRAM array are unable to store a sufficient electriccharge to cause a detectable change in voltage on a conductor whendischarged to the conductor, any “1” or “0” bits stored as electriccharges on those capacitors cannot be retrieved by the array. In thiscircumstance, the array must be repaired by replacing the failingcapacitors with redundant capacitors in redundant rows or columns in thearray. If too many of the redundant capacitors also fail, then the arraymust be discarded.

[0006] More specifically, a conventional DRAM array 10 shown in FIG. 1stores digital information in the form of “1” and “0” bits by storingthe bits as electric charges on storage capacitors 12, 14, and 16 inmemory cells 18, 20, 22 and 24 arranged along word lines (i.e., rows)WL0, WL1, . . . , and WLm and complementary pairs of digit lines (i.e.,columns) D0 and D0*, D1 and D1*, . . . , and Dn and Dn*. Of course,while the DRAM array 10 is shown in FIG. 1 as having only nine memorycells in order to simplify description, the array 10 typically includesthousands or millions of memory cells.

[0007] The DRAM array 10 stores a “1” bit in the memory cell 18, forexample, by energizing the word line WL0 to activate an NMOS transistor26. The DRAM array 10 then applies a “1” bit voltage equal to a supplyvoltage V_(CC) cc (e.g., 3.3 Volts) to the digit line D0, causingcurrent to flow from the digit line D0, through the activated NMOStransistor 26 and the storage capacitor 12, and to a cell plate voltageDVC2 typically equal to one half the supply voltage V_(CC). As thiscurrent flows, the storage capacitor 12 stores positive electric chargereceived from the digit line D0, causing a voltage V_(S1) on the storagecapacitor 12 to increase. When the voltage V_(S1) on the storagecapacitor 12 equals the “1” bit voltage on the digit line D0, currentstops flowing through the storage capacitor 12. A short time later, theDRAM array 10 de-energizes the word line WL0 to de-activate the NMOStransistor 26 and isolate the storage capacitor 12 from the digit lineD0, thereby preventing the positive electric charge stored on thestorage capacitor 12 from discharging back to the digit line D0.

[0008] Similarly, the DRAM array 10 stores a “0” bit in the memory cell20, for example, by energizing the word line WL1 to activate an NMOStransistor 28. The DRAM array 10 then applies a “0” bit voltageapproximately equal to a reference voltage V_(SS) (e.g., 0.0 Volts) tothe digit line D0, causing current to flow from the cell plate voltageDVC2, through the storage capacitor 14 and the activated NMOS transistor28, and to the digit line D0. As this current flows, the storagecapacitor 14 stores negative electric charge received from the digitline D0, causing a voltage V_(S2) on the storage capacitor 14 todecrease. When the voltage V_(S2) equals the “0” bit voltage on thedigit line D0, current stops flowing through the storage capacitor 14. Ashort time later, the DRAM array 10 de-energizes the word line WL1 todeactivate the NMOS transistor 28 and isolate the storage capacitor 14from the digit line D0, thereby preventing the negative electric chargestored on the storage capacitor 14 from discharging back to the digitline D0.

[0009] The DRAM array 10 stores “1” and “0” bits in the memory cells 22arranged along the complementary digit lines D0*, D1*, . . . , and Dn*in a manner similar to that described above, with the exception that the“1” bit voltage for these cells is approximately equal to the referencevoltage V_(SS) and the “0” bit voltage equals the supply voltage V_(CC).

[0010] The DRAM array 10 retrieves “1” and “0” bits stored in the mannerdescribed above in the memory cells 18, 20, 22, and 24 by dischargingelectric charges stored on the storage capacitors 12, 14, and 16 to thedigit lines D0, D0*, D1, D1*, . . . , Dn, and Dn* and then detecting achange in voltage on the digit lines D0, D0*, D1, D1*, . . . , Dn, andDn* resulting from the discharge with sense amplifiers (0), (1), . . .,and (n).

[0011] For example, the DRAM array 10 retrieves the “1” bit stored inthe memory cell 18 by first equilibrating the voltages on the digitlines D0 and D0* to the cell plate voltage DVC2. The DRAM array 10 thenenergizes the word line WL0 to activate the NMOS transistor 26, causingthe positive electric charge stored on the storage capacitor 12 todischarge through the activated NMOS transistor 26 to the digit line D0.As the positive electric charge discharges, the voltage on the digitline D0 rises by an amount V_(SENSE) calculated as follows:

V _(SENSE)=(V _(S) 31 DVC2)*C _(S)/(C _(D) +C _(S))

[0012] where V_(S) is the voltage V_(S1) on the storage capacitor 12,C_(S) is the capacitance of the storage capacitor 12, and C_(D) is thecapacitance of the digit line D0. When the rise in voltage V_(SENSE) onthe digit line D0 causes a difference in voltages between the digitlines D0 and D0* to exceed a detection threshold (typically about 150mVolts) of the sense amplifier (0), the sense amplifier (0) responds bydriving the voltage on the digit line D0 to the supply voltage V_(CC)and by driving the voltage on the digit line D0* approximately to thereference voltage V_(SS). Input/output gating circuitry, DC senseamplifiers, and an output buffer (not shown) then transmit thesevoltages from the digit lines D0 and D0* to external circuitry as a “1”bit.

[0013] Likewise, the DRAM array 10 retrieves the “0” bit stored in thememory cell 20, for example, by first equilibrating the voltages on thedigit lines D0 and D0* to the cell plate voltage DVC2. The DRAM array 10then energizes the word line WL1 to activate the NMOS transistor 28,causing the negative electric charge stored on the storage capacitor 14to discharge through the activated NMOS transistor 28 to the digit lineD0. As the negative electric charge discharges, the voltage on the digitline D0 falls by an amount V_(SENSE), calculated as described above,where V_(S) is the voltage V_(S2) on the storage capacitor 14 and C_(S)is the capacitance of the storage capacitor 14. When the drop in voltageV_(SENSE) on the digit line D0 causes the difference in voltages betweenthe digit lines D0 and D0* to exceed the detection threshold of thesense amplifier (0), the sense amplifier (0) responds by driving thevoltage on the digit line D0 approximately to the reference voltageV_(SS) and by driving the voltage on the digit line D0* to the supplyvoltage V_(CC). The input/output gating circuitry, DC sense amplifiers,and output buffer then transmit these voltages from the digit lines D0and D0* to external circuitry as a “0” bit.

[0014] The DRAM array 10 retrieves “1” and “0” bits from the memorycells 22 arranged along the complementary digit lines D0*, D1*, . . . ,and Dn* in the same manner as described above.

[0015] DRAM arrays sometimes contain defective memory cells that areunable to reliably store “1” and “0” bits in the manner described above.In some instances, this occurs because the capacitance of the storagecapacitors in these memory cells is too small, preventing the capacitorsfrom retaining a sufficient electric charge to cause a change in voltageV_(SENSE) on a digit line when discharged to the digit line that exceedsa sense amplifier's detection threshold. In other instances, this occursbecause the electric charge stored on the storage capacitors in thesememory cells leaks away through a variety of mechanisms, also preventingthe capacitors from retaining a sufficient electric charge to cause adetectable change in voltage V_(SENSE) on a digit line when dischargedto the digit line. In either case, because the change in voltageV_(SENSE) caused by discharging the electric charges stored by thestorage capacitors in these memory cells cannot be detected by a senseamplifier, the “1” and “0” bits represented by the electric chargesstored in these memory cells are unretrievable.

[0016] DRAM arrays are also sometimes unable to reliably store “1” and“0” bits in certain memory cells because the detection threshold of thecells' associated sense amplifier is too large for the sense amplifierto detect a change in voltage V_(SENSE) caused by one of the cellsdischarging to the digit line. In this case as well, the “1” and “0”bits represented by the electric charges stored in these cells areunretrievable.

[0017] Generally, when DRAM arrays are found to be defective in thisway, an attempt is made to repair the arrays by replacing defectivememory cells and defective sense amplifiers in the arrays with redundantmemory cells provided in redundant rows or columns in the arrays andwith redundant sense amplifiers provided in the redundant columns.

[0018] Conventionally, when a redundant row is used to repair a DRAMarray containing a defective memory cell, a row address that identifiesthe defective cell's row is permanently stored in the array by blowingselected fuses or anti-fuses in the array. Then, during normal operationof the DRAM array, if the array receives a request to access a memorycell having a memory address including a row address portion thatcorresponds to the stored row address, redundant circuitry in the arraydirects the array to access a redundant memory cell in the redundant rowinstead of accessing the memory cell identified by the received memoryaddress. Since every memory cell in the defective cell's row has thesame row address, every cell in the defective cell's row, both operativeand defective, is replaced by a redundant memory cell in the redundantrow.

[0019] Similarly, when a redundant column is used to repair a DRAM arraycontaining a defective memory cell, a column address that identifies thedefective cell's column is permanently stored in the array by blowingselected fuses or anti-fuses in the array. Then, during normal operationof the DRAM array, if the array receives a request to access a memorycell having a memory address including a column address portion thatcorresponds to the stored column address, redundant circuitry in thearray directs the array to access a redundant memory cell in theredundant column instead of accessing the memory cell identified by thereceived memory address. Since every memory cell in the defective cell'scolumn has the same column address, every cell in the defective cell'scolumn, both operative and defective, is replaced by a redundant memorycell in the redundant column.

[0020] The process described above for repairing a DRAM array usingredundant rows and columns is well known in the art, and is described invarious forms in U.S. Pat. Nos. 4,459,685, 4,601,019, 5,422,850 and5,528,539.

[0021] Because the conventional repair process described above uses anentire redundant row or column to repair each defective memory cell in aDRAM or other memory array, the number of defective memory cells thatcan be repaired in an array is limited by the number of redundant rowsor columns in the array which, in turn, is limited by the spaceavailable in the array for redundant rows or columns. As a result, it isnot uncommon for defective DRAM and other memory arrays to be discardedbecause the conventional repair process cannot repair the quantity ofdefective memory cells they contain. This problem is often exacerbatedby the discovery of defective redundant memory cells in the availableredundant rows or columns. Obviously, it would be preferable to be ableto repair these defective arrays rather than discard them.

[0022] Therefore, there is a need in the art for an improved device andmethod for repairing DRAM arrays and other memory arrays. Such animproved device and method should be applicable to arrays containingmemory cells that are unable to reliably store “1” and “0” bits becausetheir storage capacitors do not retain a sufficient electric charge, orbecause their associated sense amplifiers have a detection thresholdthat is too large.

BRIEF SUMMARY OF THE INVENTION

[0023] The present invention provides an apparatus for repairing amemory array, such as a DRAM array, that includes a pair ofcomplementary digit lines through which memory cells activated by wordlines selected in accordance with row addresses are accessed. The arraymay need repair, for example, when a memory cell in the array is unableto properly store “1” and “0” bits because the charge it retainsrepresenting a bit is not sufficient to cause a detectable change involtage on one of the digit lines when discharged to the digit line.

[0024] When repair is needed, enabling circuitry (e.g., fuses oranti-fuses) in the apparatus enables repair of the array, and word lineenergizing circuitry (e.g., a row decoder) responsive to the enablingcircuitry energizes more than one word line in the array in accordancewith each row address so more than one memory cell is accessed throughthe digit lines for each row address. As a result, the apparatus storesa single “1” or “0” bit as a charge in multiple memory cells. Then, whenthe apparatus retrieves the single bit, the bit's representative chargesstored in the multiple memory cells are discharged to the digit lines tocause a change in voltage on the digit lines that is greater than, andtherefore more likely to be detectable than, a change in voltage on thedigit lines caused by discharging a representative charge stored in asingle memory cell to the digit lines in the conventional manner.

[0025] In other embodiments of the present invention, a memory system,an integrated circuit die, and a semiconductor wafer include the repairapparatus and memory array described above. In another embodiment, anelectronic system includes input, output, processor, and memory devices,and the memory device includes the repair apparatus and memory arraydescribed above.

[0026] In a further embodiment, the present invention provides anapparatus for repairing a memory array. The memory array is of the typein which stored bits are read by detecting a change in voltage betweentwo conductors caused by sharing a charge stored in a memory cell in thearray with one of the conductors. The apparatus repairs the array whensome memory cells in the array cannot retain a sufficient charge tocause a detectable change in voltage on one of the conductors. Theapparatus includes circuitry directing each memory cell in a group ofcells in the array to store a charge representing a single stored bitand, when the single stored bit is being read, to share its storedcharge with one of the conductors.

[0027] In a still further embodiment, the present invention provides anapparatus for repairing a memory array. The memory array is of the typein which stored bits are accessed by using sense amplifiers to detect achange in voltage between two conductors caused by sharing a chargestored in a memory cell in the array with one of the conductors. Theapparatus repairs the array when some of the sense amplifiers in thearray cannot detect a change in voltage on one of the conductors causedby sharing a charge stored in one of the memory cells with one of theconductors. The apparatus includes circuitry directing each memory cellin a group of cells in the array to store a charge representing a singlestored bit and, when the single stored bit is being accessed, to shareits stored charge with one of the conductors.

[0028] In an additional embodiment, a memory system includes a memoryarray including pairs of complementary digit lines, alternating even andodd word lines, and memory cells controlled by the word lines andaccessed through the digit lines. Address buffers receive memoryaddresses and output corresponding row and column addresses, and rowdecoder circuitry energizes at least two word lines in accordance witheach row address. A column decoder outputs a column select signal inaccordance with each column address, and sense amplifier andinput/output gating circuitry selects a pair of complementary digitlines in the array in accordance with each column select signal. As aresult, two or more memory cells that are each controlled by one of theenergized word lines are accessed through one of the selected digitlines. A data buffer provides communication between the accessed memorycells and external circuitry.

[0029] In a further embodiment, a memory system includes a memory arrayincluding pairs of complementary digit lines, word lines, and memorycells controlled by the word lines and accessed through the digit lines.Address buffers receive multiplexed memory addresses in the form of afirst plurality of address bits followed in time by a second pluralityof address bits. The address buffers also output a row address and afirst portion of a column address corresponding to each memory address'associated first plurality of address bits, and output a second portionof the column address corresponding to each memory address' associatedsecond plurality of address bits. Row decoder circuitry energizes atleast two word lines in accordance with each row address, and a columndecoder outputs a column select signal in accordance with the first andsecond portions of each column address. Sense amplifier and input/outputgating circuitry selects a pair of complementary digit lines in thearray in accordance with each column select signal so at least twomemory cells controlled by the energized word lines are accessed throughone of the selected digit lines. As a result, the accessed memory cellstogether may store or output a single memory bit to external circuitry.A data buffer provides communication between the accessed memory cellsand external circuitry.

[0030] In a still further embodiment, a memory system includes a memoryarray including pairs of complementary digit lines, word lines, andmemory cells controlled by the word lines and accessed through the digitlines. Row address bit terminals receive a first plurality of addressbits associated with a non-multiplexed memory address, and columnaddress bit terminals receive a second plurality of address bitsassociated with the non-multiplexed memory address. Address buffersoutput a row address corresponding to a first portion of the firstplurality of address bits and output a column address corresponding toboth the second plurality of address bits and a second portion of thefirst plurality of address bits. Row decoder circuitry energizes atleast two word lines in accordance with the row address, and a columndecoder outputs a column select signal in accordance with the columnaddress. Sense amplifier and input/output gating circuitry selects apair of complementary digit lines in the array in accordance with thecolumn select signal. As a result, at least two memory cells controlledby the energized word lines are accessed through one of the selecteddigit lines. A data buffer provides communication between the accessedmemory cells and external circuitry.

[0031] In a still additional embodiment, a method for storing a bit in amemory array having a plurality of memory cells each coupled to one of apair of complementary digit lines includes providing a chargerepresenting the bit on each of the digit lines, storing the chargeprovided on one of the digit lines in at least one of the memory cells,and storing the charge provided on one of the digit lines in at leastone other of the memory cells.

[0032] In another embodiment, a method of testing a repair for a memoryarray of the type to store a bit by storing a charge in a memory cell,and also of the type to access the bit by sharing the stored charge withone of two conductors and then detecting a resulting change in voltagebetween the conductors, comprises: directing the memory cells in a groupof memory cells in the memory array to each store the same bit by eachstoring a charge representing the bit; directing each memory cell in thegroup of memory cells to share its stored charge with one of theconductors; and attempting to detect a change in voltage between theconductors resulting from the memory cells in the group sharing theirstored charges with the conductors.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

[0033]FIG. 1 is a schematic of a conventional dynamic random accessmemory array;

[0034]FIG. 2 is a block diagram and schematic of a memory system inaccordance with the present invention;

[0035]FIGS. 3A, 3B, and 3C are schematics of alternative versions of arepair enable circuit in the memory system of FIG. 2;

[0036]FIG. 4 is a block diagram of a modified version of the memorysystem of FIG. 2;

[0037]FIG. 5 is a diagram of a semiconductor wafer including anintegrated circuit die incorporating the memory system of FIG. 2; and

[0038]FIG. 6 is a block diagram of an electronic system including amemory device incorporating the memory system of FIG. 2.

DETAILED DESCRIPTION OF THE INVENTION

[0039] In general, the present invention provides an improved device andmethod for repairing Dynamic Random Access Memory (DRAM) arrays andother memory arrays. The device and method repair arrays that, forexample, contain memory cells that are defective as a result of beingunable to retain an electric charge representing a “1” or “0” bit thatis sufficient to cause a detectable change in voltage on a digit linewhen discharged to the digit line.

[0040] The device and method store an electric charge representing anindividual “1” or “0” bit in multiple memory cells in an array thatshare a pair of complementary digit lines. When a bit stored in thisinventive manner is retrieved, the electric charges stored in themultiple memory cells are discharged to the pair of digit lines, causinga detectable change in voltage on the digit lines. The device and methodthus “gang” memory cells together to repair an array.

[0041] More particularly, as shown in FIG. 2, an inventive memory system30 includes row and column address buffers 32 and 34 receiving amultiplexed Memory Address, a row address strobe signal RAS*, and acolumn address strobe signal CAS*. It will be understood by those havingskill in the field of this invention that the address buffers 32 and 34may comprise any circuitry for buffering memory addresses, including,for example, pre-decoders and array buffers. Also, it will be understoodthat the present invention is applicable to memory systems receiving anynumber of address bits in any configuration, including both multiplexedand non-multiplexed addressing schemes. Further, as used herein, a“multiplexed” Memory Address is an address that is provided to a memorysystem in the form of a first plurality of address bits (e.g., the rowaddress bits in a typical DRAM system) followed in time by a secondplurality of address bits (e.g., the column address bits in a typicalDRAM system).

[0042] The memory system 30 operates in both an unrepaired state and arepaired state. In its unrepaired state, in response to RAS* beingactivated, the row address buffers 32 operate in a well known manner tolatch in a first plurality of address bits A0, A1, . . ., and Az fromthe Memory Address and then output a corresponding Row Address thatincludes row address bits RA0, RA1, . . . , RAz. A sense amplifier (0)also equilibrates voltages on a pair of complementary digit lines D0 andD0* to the cell plate voltage DVC2.

[0043] In addition, a repair enable circuit 36 is configured in theunrepaired state to allow normal operation of the memory system 30 byoutputting a high, inactive repair enable signal REP_EN* to inputs offirst and second NAND gates 38 and 40. As a result, when the row addressbit RA0 is high, the NAND gate 38 outputs a low, inactive odd rowdecoder enabling signal O_EN to disable an odd row decoder 42 and, atthe same time, an inverter 44 outputs a low, causing the NAND gate 40 tooutput a high, active even row decoder enabling signal E_EN to enable aneven row decoder 46. The enabled even row decoder 46 then energizes oneof a plurality of even word lines (i.e., rows) WL0 and WL2 in a DRAMarray 48 selected in accordance with the row address bits RA1, . . .,Raz in a well known manner.

[0044] When, instead, the row address bit RA0 is low, the NAND gate 38outputs a high, active odd row decoder enabling signal O_EN to enablethe odd row decoder 42 and, at the same time, the inverter 44 outputs ahigh, causing the NAND gate 40 to output a low, inactive even rowdecoder enabling signal E_EN to disable the even row decoder 46. Theenabled odd row decoder 42 then energizes one of a plurality of odd wordlines WL1 and WL3 selected in accordance with the row address bits RA1,. . . , Raz in a well known manner.

[0045] As will be described in more detail below with respect to FIGS.3A, 3B, and 3C, the repair enable circuit 36 may comprise any circuitryfor enabling repair of an array, including, for example, fuses oranti-fuses. Also, as used herein, “configure,” “configuring,” and“configured” include both an affirmative act with respect to a circuit(e.g., blowing a fuse or an anti-fuse) and the absence of an affirmativeact with respect to the circuit (e.g., not blowing a fuse or ananti-fuse). Further, it will be understood that the present invention isnot limited to enabling circuitry including the repair enable circuit 36and NAND gates 38 and 40. Rather, the present invention includes withinits scope any circuitry capable of enabling repair of an array. Inaddition, it will be understood that the row decoders 42 and 46 maycomprise any word line energizing circuitry, including, for example,phase drivers and word line drivers. Still further, it will beunderstood that while only four word lines are shown in FIG. 2 forpurposes of clarity, any number of word lines will work for purposes ofthe present invention. Also, it will be understood that while thepresent invention is described with respect to the DRAM array 48, thepresent invention is applicable to other memory arrays.

[0046] If, for example, the even word line WL0 is energized, asdescribed above, in the unrepaired state of the memory system 30, theenergized even word line WL0 activates an NMOS transistor 50 in a memorycell 52 in the DRAM array 48 through a control terminal 53 of the NMOStransistor 50. Of course, while the DRAM array 48 is shown in FIG. 2 ashaving only four memory cells for clarity, it will be understood thatthe DRAM array 48 includes millions of memory cells, and that thepresent invention is applicable to arrays including any number of memorycells.

[0047] As a result of the NMOS transistor 50 being activated, a storagecapacitor 54 storing a positive electric charge representing a “1” bit,for example, is connected to the digit line D0 through the activatedNMOS transistor 50 and an access terminal 55 (e.g., a digit linecontact). Of course, while only one pair of complementary digit lines D0and D0*, and only one sense amplifier (0), are shown in FIG. 2 forclarity, it will be understood that the DRAM array 48 includes amultitude of digit lines and sense amplifiers, and that the presentinvention includes within its scope any number of digit lines and senseamplifiers.

[0048] When the storage capacitor 54 is connected to the digit line D0through the activated NMOS transistor 50 and the access terminal 55, thestorage capacitor 54 discharges its positive electric charge to thedigit line D0. As a result, a voltage on the digit line D0 rises byV_(SENSE) as calculated above. During the same period of time, inresponse to CAS* being activated, the column address buffers 34 operatein a well known manner to latch in a second plurality of address bitsA0, A1, . . . , and Az from the Memory Address and then output acorresponding Column Address to a column decoder 56.

[0049] If the positive electric charge stored in the storage capacitor54 is sufficient for V_(SENSE) to exceed a detection threshold of thesense amplifier (0), the sense amplifier (0) detects the change involtage V_(SENSE) and, in response, drives the digit line D0 to thesupply voltage V_(CC) and the digit line D0* approximately to thereference voltage V_(SS). The column decoder 56 then energizes a columnselect signal CSEL_0 selected in accordance with the Column Address in awell known manner, thereby activating a pair of input/output gating NMOStransistors 58 and 60. As a result, the voltages on the digit lines D0and D0* are transferred through an input/output bus <I/O, I/O*> to adata buffer 62 including well known DC sense amplifiers 64, an outputbuffer 66, write drivers 68, and an input buffer 70. The data buffer 62then outputs the “1” bit as an output data signal Q to externalcircuitry (not shown). Of course, it will be understood that the presentinvention is not limited to data buffers including DC sense amplifiers,output buffers, write drivers, and input buffers.

[0050] If, instead, the positive electric charge stored in the storagecapacitor 54 is insufficient for V_(SENSE) to exceed the detectionthreshold of the sense amplifier (0), or the detection threshold of thesense amplifier (0) is too large, the sense amplifier (0) does notdetect the change in voltage V_(SENSE), and the voltages on the digitlines D0 and D0* do not separate as desired. As a result, the “1” bit(and any other bit) stored on the storage capacitor 54 is unretrievable,and the memory system 30 requires repair.

[0051] If only a few memory cells in the memory system 30 requirerepair, conventional methods using redundant rows and columns to replacethese memory cells may work to repair the memory system 30. For example,the word line WL3 may comprise a redundant word line so that the failingmemory cell 52 is replaced with a memory cell 72 along the word lineWL3. However, as described above, conventional methods are not alwayssuccessful.

[0052] Refresh counter circuitry 73, such as a CBR (CAS Before RAS)refresh counter, is operative in a well-known manner in the unrepairedstate of the memory system 30.

[0053] Repair of the memory system 30 is enabled in accordance with thepresent invention by configuring the repair enable circuit 36 to outputa low, active repair enable signal REP_EN* to inputs of the first andsecond NAND gates 38 and 40. As a result, the first NAND gate 38 outputsa high, active odd row decoder enabling signal O_EN to enable the oddrow decoder 42. At the same time, the second NAND gate 40 also outputs ahigh, active even row decoder enabling signal E_EN to enable the evenrow decoder 46.

[0054] In the repaired state of the memory system 30, in response toRAS* being activated, the row address buffers 32 operate in the samewell known manner to latch in the first plurality of address bits A0,A1, . . ., and Az from the Memory Address and then output acorresponding Row Address that includes row address bits RA0, RA1, . .., RAz. The sense amplifier (0) also equilibrates the voltages on thedigit lines D0 and D0* to the cell plate voltage DVC2.

[0055] Because the even row decoder 46 is enabled in the repaired stateof the memory system 30 as described above, it energizes an even wordline WL0 or WL2 selected in accordance with the row address bits RA1, .. ., RAz. As a result, the NMOS transistor 50 or an NMOS transistor 74is activated, connecting the storage capacitor 54 or a storage capacitor76, respectively, to the respective digit line D0 or D0* through theactivated NMOS transistor 50 or 74 and the access terminal 55 or anaccess terminal 77 (e.g., a digit line contact). At the same time,because the odd row decoder 42 is also enabled in the repaired state, itenergizes an odd word line WL1 or WL3 also selected in accordance withthe row address bits RA1, . . ., RAz. As a result, an NMOS transistor 78or 80 is activated, connecting a respective storage capacitor 82 or 84to the respective digit line D0 or D0* through the activated NMOStransistor 78 or 80 and the respective access terminal 55 or 77.

[0056] With two of the storage capacitors 54, 76, 82, and 84 eachconnected to one of the digit lines D0 and D0* as described above, thememory system 30 can store a “1” or “0” bit on the connected capacitors.To store a “1” bit, for example, received by the input buffer 70 as aninput data signal D, the input buffer 70 directs the write drivers 68 todrive the input/output bus <I/O, I/O*> to the supply voltage V_(CC)(I/O) and approximately to the reference voltage V_(SS) (I/O*). Duringthe same period of time, in response to CAS* being activated, the columnaddress buffers 34 operate in the same well known manner to latch in thesecond plurality of address bits A0, A1, . . . , Az from the MemoryAddress and output a corresponding Column Address to the column decoder56. In response, the column decoder 56 energizes the column selectsignal CSEL_0 selected in accordance with the Column Address, therebyactivating the input/output gating NMOS transistors 58 and 60 andconducting the input/output bus <I/O, I/O*> voltages to the senseamplifier (0). The sense amplifier (0) responds by driving the digitlines D0 and D0* to the respective supply voltage V_(CC) and referencevoltage V_(SS). These voltages are then stored as described above on thetwo of the storage capacitors 54, 76, 82, and 84 that are each connectedto one of the digit lines D0 and D0*.

[0057] Of course, the memory system 30 can also retrieve a “1” or “0”bit stored on two of the storage capacitors 54, 76, 82, and 84. To doso, the even and odd row decoders 46 and 42, respectively, energize oneof the even word lines WL0 and WL2 and one of the odd word lines WL1 andWL3 each selected in accordance with the row address bits RA1, . . . ,RAz as described above. As a result, for example, positive electriccharges representing a “1” bit stored on the storage capacitors 54 and82 may discharge through respective NMOS transistors 50 and 78 activatedby respective energized word lines WL0 and WL1. These dischargingpositive electric charges raise the voltage on the digit line D0 byV_(SENSE) as described above, except that the rise in voltage V_(SENSE)is greater than it would have been had the “1” bit been stored in theconventional manner as a charge on only one of the storage capacitors54, 76, 82, and 84. This “greater” V_(SENSE) is, of course, more likelyto exceed the detection threshold of the sense amplifier (0) and tothereby be detected. As a result, the “1” bit may be successfullyretrieved through the sense amplifier (0), the input/output gating NMOStransistors 58 and 60, the input/output bus <I/O, I/O*>, and the databuffer 62 in the manner described above. Thus, the memory system 30,including any previously defective memory cells, is repaired.

[0058] It should be understood that the present invention works with twoor more memory cells connected to the same digit line D0 or D0*, forexample, as described above, and with one or more memory cells connectedto the digit line D0 and one or more memory cells connected to the digitline D0*. Further, it should be understood that while the memory system30 has been described as including both odd and even row decoders 42 and46, the present invention includes within its scope any decodingcircuitry capable of energizing two or more word lines in accordancewith each Memory Address. In addition, it should be understood that thepresent invention includes within its scope the energizing of adifferent number of word lines for different row addresses (e.g.,energizing two word lines for a first row address and four word linesfor a second row address). Such a scheme may be desirable where morememory cells are necessary to repair an array in some locations than inothers.

[0059] It should also be understood that the memory system 30 has lesstotal storage capacity in its repaired state than in its unrepairedstate. For example, if the memory system 30 is provided in a 16 MegabitX 1 configuration in its unrepaired state, it has 2¹² uniquelyaddressable word lines (i.e., rows) and 2¹² uniquely addressable pairsof digit lines (i.e., columns) for a total of 2²⁴ uniquely addressablelocations (i.e., memory cells). If the memory system 30 is then repairedin accordance with the present invention by enabling the accessing oftwo memory cells for each received memory address, the repaired memorysystem 30 has 2¹¹ uniquely addressable pairs of word lines and 2¹²uniquely addressable pairs of digit lines for a total of 2²³ uniquelyaddressable locations (i.e., pairs of memory cells). As a result, therepaired memory system 30 is in an 8 Megabit X 1 configuration. If,instead, the memory system 30 is repaired by enabling the accessing offour memory cells for each received memory address, the repaired memorysystem 30 has 2¹⁰ uniquely addressable groups of four word lines and 2¹²uniquely addressable pairs of digit lines for a total of 2²² uniquelyaddressable locations (i.e., groups of four memory cells). As a result,the repaired memory system 30 is in a 4 Megabit X 1 configuration. Ofcourse, in order to enable the accessing of four memory cells for eachreceived memory address, the even and odd row decoders 46 and 42 areeach configurable with, for example, fuses or anti-fuses, to select andenergize two word lines in accordance with each row address.

[0060] It will be understood that, as used herein, “accessing” a memorycell means energizing a conductor, such as a word line, connected to anaccess terminal of the cell, and then sensing a resulting change involtage on the conductor using a sense amplifier. The term “accessing”thus includes both refreshing and reading a memory cell.

[0061] Since the 4 Megabit X 1 configuration produced in the aboveexample by grouping four word lines together for each memory address isan industry standard configuration and the 8 Megabit X 1 configurationis not, it can be seen that it can be advantageous to group four wordlines together when repairing the memory system 30 in accordance withthe present invention. This allows 256 Megabit arrays to be recovered(i.e., repaired) as industry standard 64 Megabit arrays, 64 Megabitarrays to be recovered as industry standard 16 Megabit arrays, 16Megabit arrays to be recovered as industry standard 4 Megabit arrays, 4Megabit arrays to be recovered as industry standard 1 Megabit arrays,etc. Of course, the same advantageous principle applies to groupingsixteen, sixty-four, etc. word lines together when repairing the memorysystem 30 in accordance with the present invention.

[0062] Of course, 8 Megabit, 32 Megabit, 128 Megabit, etc.configurations can be useful, for example, in producing standard SingleIn-Line Memory Module (SIMM) upgrade configurations.

[0063] However, continuing with the above example, if the unrepairedmemory system 30 having a 16 Megabit X 1 configuration is to berecovered in accordance with the present invention in a 4 Megabit X 1configuration, it is necessary that the column address buffers 34continue to receive the twelve address bits with each memory addressthat they received in the 16 Megabit X 1 configuration. This is becausein both the unrepaired 16 Megabit X 1 configuration and the repaired 4Megabit X 1 configuration, the memory system 30 has 2¹² uniquelyaddressable pairs of digit lines. Allowing the column address buffers 34to continue to receive twelve address bits in the repaired 4 Megabit X 1configuration can be problematic, though, because standard die packagesfor 4 Megabit X 1 dice include only eleven address bit terminals.

[0064] Therefore, still continuing with the above example, in therepaired 4 Megabit X 1 configuration, the column address buffers 34 inthe memory system 30 are preferably configurable with, for example,fuses or anti-fuses, to latch in an address bit in the first elevenaddress bits from the Memory Address in response to RAS* beingactivated. At the same time, of course, the row address buffers 32 latchin the other ten address bits from the Memory Address in response toRAS* being activated in order to be able to uniquely address the 2¹⁰groups of four word lines in the memory system 30. Later, in response toCAS* being activated, the column address buffers 34 latch in the secondeleven address bits from the Memory Address in order to have a total oftwelve address bits from the Memory Address to uniquely address the 2¹²pairs of complementary digit lines in the memory system 30.

[0065] Of course, it should be understood that the refresh countercircuitry 73 of the memory system 30 may be configured with fuses,anti-fuses, or the like to output row addresses in the repaired state ofthe memory system 30 which correspond appropriately to those addressesoutput by the row address buffers 32.

[0066] As shown in FIG. 3A, the repair enable circuit 36 includes aplurality of fuses 86 that are configurable to cause the repair enablecircuit 36 to output the low, active repair enable signal REP_EN*. Thefuses 86 may be configured in a well known manner by laser or electriccurrent. As shown in FIG. 3B, the repair enable circuit 36 includes aplurality of anti-fuses 88 that are also configurable to cause therepair enable circuit 36 to output the low, active repair enable signalREP_EN*. The anti-fuses 88 may be configured in a well known manner witha programming voltage. As shown in FIG. 3C, the repair enable circuit 36is configurable in response to a test mode enable signal TEST_EN fromexternal circuitry (not shown) to cause the repair enable circuit 36 tooutput the low, active repair enable signal REP_EN*. Such aconfiguration is desirable so repair of an array in accordance with thepresent invention may be tested in a temporary manner before it isimplemented in a permanent manner using fuses, anti-fuses, or the like.

[0067] A modified version of the memory system 30 of FIG. 2 is shown inFIG. 4. In this modified version, row and column address buffers 90 and92 receive a non-multiplexed memory address 94 in the repaired, 4Megabit X 1 state of the memory system 30. The memory address 94includes row address bits R0, . . . , and R9 provided through rowaddress bit die bond pads 96 and column address bits C0, C1, . . . , C11provided through column address bit die bond pads 98 and one of the rowaddress bit die bond pads 96. As a result, the column address buffers 92receive the twelve address bits necessary to uniquely address the 2¹²pairs of digit lines in the memory system 30, and the row addressbuffers 90 receive the ten address bits necessary to uniquely addressthe 2¹⁰ groups of four word lines in the memory system 30. At the sametime, the memory system 30 is recovered from its unrepaired 16 Megabit X1 configuration in a repaired 4 Megabit X 1 configuration that is pincompatible with the eleven standard pins in 4 Megabit die packages. Ofcourse, it will be understood that the unrepaired, 16 Megabit X 1configuration and repaired, 4 Megabit X 1 configuration for the memorysystem 30 described above are only examples, and that the presentinvention is therefore not so limited.

[0068] As shown in FIG. 5, a semiconductor wafer 100 includes ayet-to-be cut integrated circuit die 102 that incorporates the memorysystem 30 of FIG. 2.

[0069] As shown in FIG. 6, an electronic system 104 includes an inputdevice 106, an output device 108, and a memory device 110, all coupledto a processor device 112. The memory device 110 incorporates the memorysystem 30 of FIG. 2.

[0070] The present invention thus provides an improved device and methodfor repairing DRAM and other memory arrays. By grouping two or more wordlines together for each memory address, the present invention whenapplied to a DRAM array effectively halves the time it takes to refreshthe array. The present invention also reduces the time T_(RAC) in a DRAMarray from the activation of RAS* to the outputting of valid databecause the greater charge applied by the present invention to thearray's digit lines for each “1” or “0” bit retrieved from the arrayallows the sense amplifiers in the array to more quickly detect a bitbeing retrieved. Further, the greater charge applied by the presentinvention to a DRAM array's digit lines for each “1” or “0” bitretrieved from the array makes the retrieval of bits from the array lesssensitive to fluctuations in the supply voltage V_(CC) and the referencevoltage V_(SS).

[0071] Although the present invention has been described with referenceto a particular embodiment, the invention is not limited to thisdescribed embodiment. For example, it should be understood that whilethe described embodiment has been described with respect to memory cellsactivated in accordance with row addresses and accessed in accordancewith column addresses, the present invention is equally applicable tomemory systems in which the memory cells are activated in accordancewith column addresses and accessed in accordance with row addresses.Therefore, the invention is limited only by the appended claims, whichinclude within their scope all equivalent devices or methods whichoperate according to the principles of the invention as described.

What is claimed is:
 1. A memory system having a dynamic memory array,comprising: an enabling device used with said dynamic memory systemhaving said dynamic memory array, said enabling device including atleast two programmable elements selected from a group comprising a fuseand an anti-fuse; said memory array comprising: a plurality of pairs ofcomplementary digit lines; a plurality of word lines; a plurality ofmemory cells, each memory cell of said plurality of memory cells havinga control terminal connected to one word line of the plurality of wordlines and an access terminal connected to one digit line of a pair ofcomplementary digit lines of the plurality of pairs of complementarydigit lines, at least two memory cells of the plurality of memory cellsconnected to each digit line of a complementary pair of digit lines ofthe plurality of pairs of complementary digit lines, said each memorycell of said plurality of memory cells having a row address; refreshcounter circuitry and address buffer circuitry used to generate at leastone row address for at least one memory cell of said plurality of memorycells, the refresh counter circuitry comprising CAS-Before-RAS refreshcounter circuitry; row decoder circuitry connected to the plurality ofword lines and the address buffer circuitry used to energize at leasttwo word lines of the plurality of word lines in the dynamic memoryarray in accordance with said at least one row address generated by saidrefresh counter circuitry and said address buffer circuitry; senseamplifier circuitry connected to the plurality of pairs of complementarydigit lines used to access and refresh the plurality of memory cellscoupled to each of the energized said at least two word lines of saidplurality of word lines; and energizing circuitry connected to theenabling device used to energize more than one word line of the wordlines of the plurality of word lines in the memory array for said atleast one row address generated by said refresh counter circuitry andsaid address buffer circuitry for a memory cell of the plurality ofmemory cells in response to the enabling device used with said memorysystem having the memory array so that more than at least one memorycell of the plurality of memory cells accessible through the pluralityof pairs of complementary digit lines may be accessed for said at leastone row address generated by said refresh counter circuitry and saidaddress buffer circuitry.
 2. A memory system comprising: a dynamicmemory array comprising: at least two pairs of complementary digitlines; at least two alternating even and odd word lines; a plurality ofmemory cells each memory cell of the plurality of memory cells having acontrol terminal coupled to one of the at least two alternating even andodd word lines and an access terminal coupled to one of the at least twopairs of complementary digit lines; address buffers for receiving memoryaddresses and outputting corresponding row and column addresses; rowdecoder circuitry coupled to the dynamic memory array and the addressbuffers for energizing at least two word lines in the dynamic memoryarray in accordance with each corresponding row address, the row decodercircuitry comprising: refresh enable circuitry configurable to output aneven row decoder enabling signal and an odd row decoder enabling signal;an even row decoder coupled to the refresh enable circuitry, the dynamicmemory array, and the address buffers, and enable in response to theeven row decoder enabling signal to energize one or more even word linesin the memory array in accordance with each corresponding row address;and an odd row decoder coupled to the refresh enable circuitry, thedynamic memory array, and the address buffers and enable in response tothe odd row decoder enabling signal to energize one or more odd wordlines in the memory array in accordance with each corresponding rowaddress; a column decoder coupled to the address buffers for outputtingcorresponding row and column addresses; sense amplifier and input/outputgating circuitry coupled to the column decoder and the dynamic memoryarray for selecting a pair of the at least two pairs of complementarydigit lines in the memory array in accordance with each column selectsignal in order to access two or more memory cells in the memory arrayeach coupled to one of the selected digit lines of the at least twopairs of complementary digit lines and one of the at least two energizedword lines; and a data buffer coupled to the sense amplifier andinput/output gating circuitry for communication between the accessedmemory cells and external circuitry.
 3. A memory system comprising: adynamic memory array comprising: at least two pairs of complementarydigit lines; at least two odd word lines; a plurality of memory cellseach memory cell of the plurality of memory cells having a controlterminal coupled to one of the at least two odd word lines and an accessterminal coupled to one of the at least two pairs of complementary digitlines; address buffers for receiving multiplexed memory addresses in theform of a first plurality of address bits followed in time by a secondplurality of address bits, for outputting a row address and a firstportion of a column address for each multiplexed memory addresscorresponding to the first plurality of address bits associated with themultiplexed memory address, and for outputting a second portion of thecolumn address for each multiplexed memory address corresponding to thesecond plurality of address bits associated with the multiplexed memoryaddress, each address buffer comprising: a row address buffer receivingthe memory addresses, latching in one or more bits from each firstplurality of address bits, and outputting each corresponding rowaddress; and a column address buffer receiving the memory addresses,latching in one or more bits from each first plurality of address bits,outputting the corresponding first portion of each column address,latching in the second plurality of address bits, and outputting thecorresponding second portion of each column address; row decodercircuitry coupled to the dynamic memory array and the address buffersenergizing at least two word lines in the memory array in accordancewith each row address: a column decoder coupled to the address buffersoutputting a column select signal in accordance with the first andsecond portions of each column address; sense amplifier and input/outputgating circuitry coupled to the column decoder and the dynamic memoryarray selecting a pair of complementary digit lines of the at least twopairs of complementary digit lines in the memory array in accordancewith each column select signal accessing at least two memory cells inthe memory array, each memory cell coupled to one of the selected digitlines of the at least two pairs of complementary digit lines and one ofthe at least two energized word lines; and a data buffer coupled to thesense amplifier and input/output gating circuitry communicating betweenthe accessed memory cells and external circuitry.
 4. Apparatus used witha memory array including a pair of complementary digit lines throughwhich a plurality of memory cells activated by a plurality of word linesselected in accordance with row addresses for said plurality of memorycells may be accessed, the apparatus comprising: an enabling deviceenabling use of the apparatus with the memory array, said deviceincluding at least two programmable elements selected from a groupcomprising a fuse and an anti-fuse; and energizing circuitry coupled tothe enabling device for energizing more than one of the plurality ofword lines in the memory array in accordance with each row address for amemory cell of said plurality of memory cells in response to theenabling device enabling use of the apparatus with the memory array soat least two memory cells of the plurality of memory cells accessiblethrough the pair of complementary digit lines may be accessed for eachrow address.
 5. A memory array for stored bits accessed by detecting achange in voltage between two digit line conductors sharing a chargestored in one memory cell of a plurality of memory cells in the memoryarray with one of the two digit line conductors, an apparatus forcharging the memory array when at least one memory cell of saidplurality of memory cells in the memory array cannot retain a sufficientcharge to cause a detectable change in the voltage on said one of saidtwo digit line conductors, the apparatus comprising: circuitry fordirecting each memory cell in a group of said plurality of memory cellsto store a charge representing a single stored bit and for directingsaid each memory cell in the group of said plurality of memory cells toshare its stored charge with said one digit line of the two digit lineconductors when the single stored bit is to be accessed, said circuitryincluding row decoder circuitry.
 6. An apparatus for use with a memoryarray including a pair of complementary digit lines for activation aplurality of memory cells using a plurality of word lines selected usingrow addresses for said plurality of memory cells to be accessed, theapparatus comprising: an enabling device for enabling use of theapparatus with the memory array, said enabling device comprising atleast two programmable elements for an enable signal to temporarilyenable refreshing of the memory array, said at least two programmableelements selected from a group comprising a fuse and an anti-fuse; andenergizing circuitry coupled to the enabling device for energizing anadjacent pair of the plurality of word lines in the memory array inaccordance with each row address in response to the enabling device forenabling use of the apparatus with the memory array for an adjacent pairof the plurality of memory cells accessible through the pair ofcomplementary digit lines to be accessed for each address.
 7. Repairapparatus for a memory array including a pair of complementary digitlines through which a plurality of memory cells activated by a pluralityof word lines selected in accordance with row addresses may be accessed,the apparatus comprising: enabling circuitry for enabling charging of apair of memory cells of the plurality of memory cells of the memoryarray; and word line energizing circuitry coupled to the enablingcircuitry for energizing more than one of the plurality of word lines inthe memory array in accordance with each row address in response to theenabling circuitry enabling charging of the memory array so more thanone of the plurality of memory cells accessible through the pair ofcomplementary digit lines may be accessed for said each row address. 8.The repair apparatus of claim 7 , wherein the plurality of word lines inthe memory array comprises a plurality of alternating even and odd wordlines, wherein the enabling circuitry is configurable to output an evenrow decoder enabling signal and an odd row decoder enabling signal,wherein the word line energizing circuitry comprises: an even rowdecoder enabled in response to the even row decoder enabling signalenergizing one or more even word lines of the plurality of word lines inthe memory array in accordance with each row address; and an odd rowdecoder enabled in response to the odd row decoder enabling signal toenergizing one or more odd word lines of the plurality of word lines inthe memory array in accordance with each row address.
 9. The repairapparatus of claim 7 , wherein the enabling circuitry comprises aplurality of programmable elements selected from a group comprising afuse and an anti-fuse.
 10. The repair apparatus of claim 7 , wherein theenabling circuitry is configurable in response to a test mode enablesignal to temporarily enable charging of the memory array.
 11. Therepair apparatus of claim 7 , wherein the plurality of memory cells inthe memory array includes a plurality of redundant memory cells, whereinthe plurality of word lines in the memory array includes a plurality ofredundant word lines, wherein the word line energizing circuitry is forenergizing more than one of the plurality of redundant word lines inaccordance with selected row addresses when the enabling circuitryenables charging of the memory array so more than one of the pluralityof redundant memory cells may be accessed through the pair ofcomplementary digit lines for each of the selected row addresses. 12.The repair apparatus of claim 7 , wherein the word line energizingcircuitry is constructed to energize at least two of the plurality ofword lines in the memory array in accordance with a first row addressand to energize at least four of the plurality of word lines in thememory array in accordance with a second row address.
 13. The repairapparatus of claim 7 , wherein the word line energizing circuitry isconstructed to energize more than one of the word lines of the pluralityof word lines in the memory array in accordance with each row address inresponse to the enabling circuitry enabling charging of the memory arrayso more than one of the plurality of memory cells accessible through thepair of complementary digit lines may be refreshed for each row address.14. A dynamic memory apparatus comprising: at least one memory arraycomprising: a plurality of pairs of complementary digit lines; aplurality of word lines selectable in accordance with row addresses; anda plurality of memory cells each memory cell of the plurality of memorycells having a control terminal coupled to one of the plurality of wordlines and an access terminal coupled to one of the plurality of pairs ofcomplementary digit lines; enabling circuitry for enabling effectingrefreshing of the at least one memory array; and word line energizingcircuitry coupled to the at least one memory array and the enablingcircuitry for energizing more than one of the plurality of word lines inthe at least one memory array in accordance with each row address inresponse to the enabling circuitry effecting refreshing of the at leastone memory array so two or more of the plurality of memory cells areaccessible through each pair of the plurality of pairs of complementarydigit lines for each row address.
 15. The dynamic memory apparatus ofclaim 14 , wherein the plurality of word lines in the memory arraycomprises a plurality of alternating even and odd word lines, whereinthe enabling circuitry is configurable to output an even row decoderenabling signal and an odd row decoder enabling signal, wherein the wordline energizing circuitry comprises: an even row decoder enabled inresponse to the even row decoder enabling signal to energize one or moreeven word lines of the plurality of alternating even and odd word linesin the memory array in accordance with each row address; and an odd rowdecoder enabled in response to the odd row decoder enabling signal toenergize one or more odd word lines of the plurality of alternating evenand odd word lines in the memory array in accordance with each rowaddress.
 16. The dynamic memory apparatus of claim 14 , wherein theenabling circuitry is configured in response to a test mode enablesignal to temporarily effect refreshing of the memory array.
 17. Thedynamic memory apparatus of claim 14 , wherein the plurality of memorycells in the memory array includes a plurality of redundant memorycells, wherein the plurality of word lines in the memory array includesa plurality of redundant word lines, wherein the word line energizingcircuitry is adapted to energize more than one of the plurality ofredundant word lines in accordance with selected row addresses when theenabling circuitry enables repair of the memory array so two or more ofthe plurality of redundant memory cells are accessible through each pairof the plurality of pairs of complementary digit lines for each of theselected row addresses.
 18. An integrated circuit dynamic memory devicecomprising: at least one memory array comprising: a plurality of pairsof complementary digit lines; a plurality of word lines selectable inaccordance with row addresses; and a plurality of memory cells eachmemory cell of the plurality of memory cells having a control terminalcoupled to one of the of the plurality word lines and an access terminalcoupled to one of the of the plurality of pairs of complementary digitlines; enabling circuitry for effecting refreshing of the at least onememory array; and word line energizing circuitry coupled to the at leastone memory array and the enabling circuitry for energizing more than oneof the plurality of word lines in the at least one memory array inaccordance with each row address in response to the enabling circuitryeffecting refreshing of the at least one memory array so two or more ofthe plurality of memory cells are accessible through each pair of theplurality of pairs of complementary digit lines for each row address.19. A semiconductor wafer including at least one integrated circuitdynamic memory device comprising: at least one memory array comprising:a plurality of pairs of complementary digit lines; a plurality of wordlines selectable in accordance with row addresses; and a plurality ofmemory cells each memory cell of the plurality of memory cells having acontrol terminal coupled to one of the plurality of word lines and anaccess terminal coupled to one of the plurality of pairs ofcomplementary digit lines; enabling circuitry for enabling repair of theat least one memory array; and word line energizing circuitry coupled tothe at least one memory array and the enabling circuitry for energizingmore than one of the plurality of word lines in the at least one memoryarray in accordance with each row address in response to the enablingcircuitry effecting refreshing of the at least one memory array so twoor more of the plurality of memory cells are accessible through eachpair of the plurality of pairs of complementary digit lines for each rowaddress.
 20. An apparatus including an input device, an output device,at least one memory device, and a processor device coupled to the input,output, and the at least one memory device, the at least one memorydevice comprising: at least one memory array comprising: a plurality ofpairs of complementary digit lines; a plurality of word lines selectablein accordance with row addresses; and a plurality of memory cells eachmemory cell of the plurality of memory cells having a control terminalcoupled to one of the plurality of word lines and an access terminalcoupled to one of the plurality of pairs of complementary digit lines;enabling circuitry for enabling repair of the at least one memory array;and word line energizing circuitry coupled to the at least one memoryarray and the enabling circuitry for energizing more than one of theplurality of word lines in the at least one memory array in accordancewith each row address in response to the enabling circuitry effectingrefreshing of the at least one memory array so at least two or more ofthe plurality of memory cells are accessible through each pair of theplurality of pairs of complementary digit lines for each row address.21. In a dynamic memory device having at least one memory array forstored bits to be accessed by detecting a change in voltage between twoconductors sharing a charge stored in one of a plurality of memory cellsin the at least memory array with one of the two conductors, anapparatus for effecting refreshing the at least one memory array when atleast one memory cell of the plurality of memory cells in the memoryarray cannot retain a sufficient charge to cause a detectable change involtage on one of the two conductors, the apparatus comprising circuitryfor directing each memory cell in a group of the plurality of memorycells to store a charge representing a single stored bit and fordirecting said each memory cell in the group of the memory cells toshare its stored charge with one of the two conductors when the singlestored bit is to be accessed.
 22. The dynamic memory device of claim 21, wherein the circuitry comprises row decoder circuitry.
 23. Arefreshing apparatus for refreshing a dynamic memory array including apair of complementary digit lines through which a plurality of memorycells activated by a plurality of word lines selected in accordance withrow addresses may be accessed, the refreshing apparatus comprising:enabling circuitry for effecting refreshing of the dynamic memory array;and word line energizing circuitry coupled to the enabling circuitry forenergizing an adjacent pair of the plurality of word lines in the memoryarray in accordance with each row address in response to the enablingcircuitry effecting refreshing of the dynamic memory array so a pair ofthe plurality of memory cells accessible through the pair ofcomplementary digit lines may be accessed for each row address.
 24. Arefreshing apparatus for improved refreshing of a dynamic memory arrayincluding a plurality of pairs of complementary digit lines throughwhich a plurality of memory cells activated by a plurality of word linesselected in accordance with row addresses may be accessed, the apparatuscomprising: enabling circuitry for improving refreshing of the dynamicmemory array; and word line energizing circuitry coupled to the enablingcircuitry for energizing at least two of the plurality of word lines inthe dynamic memory array in accordance with a first row address inresponse to the enabling circuitry improved refreshing of the memoryarray so at least two of the plurality of memory cells accessiblethrough one of the plurality of pairs of complementary digit lines maybe accessed for the first row address and for energizing at least fourof the plurality of word lines in the dynamic memory array in accordancewith a second row address in response to the enabling circuitryimproving refreshing of the memory array so at least four of theplurality of memory cells accessible through one of the plurality ofpairs of complementary digit lines may be accessed for the second rowaddress.
 25. A method for determining the charging of a dynamic memoryarray of a type to store a bit by storing a charge in a memory cell, thedynamic memory array also being of a type to access the bit by sharingthe stored charge with one of two conductors and then detecting aresulting change in voltage between the one of two conductors, themethod comprising: connecting at least two memory cells in a group ofmemory cells in the dynamic memory array to the one of said twoconductors; storing the electrical charge representing the bit in the atleast two memory cells in the group of memory cells in the memory arrayby each memory cell of the plurality of memory cells storing the chargerepresenting the bit; sharing the charge stored in each memory cell ofthe at least two memory cells in the group of memory cells in the memoryarray to share its stored charge with the one of the two conductorsconnected to the at least two memory cells in the group of memory cellsin the memory array; and detecting the change in voltage between the oneof two conductors resulting from the at least two memory cells in thegroup of memory cells in the dynamic memory array connected to the oneof the two conductors sharing the stored charges in the at least twomemory cells in the group of memory cells in the memory array with theone of the two conductors connected thereto.